The present invention pertains to hunting/sport bows and more particularly, to a compound bow with an improved, low friction cable guide assembly.
The sport of bow hunting is enjoying widespread popularity. Today, the compound bow is widely used and preferred by many bow hunters and sports enthusiasts. This is because the compound bow provides the advantages of enhanced accuracy coupled with lessened force at full draw due to the mechanical advantage afforded by the compound nature of the bow.
As is known, the mechanical advantage afforded by the compound bow is created by a continuous cable comprised of a tensioning cable connected to a bowstring and passing between two eccentric wheels rotatably mounted at the ends of the limbs. The interaction of the tensioning cable with the wheels during drawing provides a multiplication of force. The action of the eccentric wheels advantageously provides a reduction in the force required during the last half of the draw. This allows the archer to maintain the full draw with reduced effort. As a result, the archer is better able to concentrate on aiming.
A further advantage of the compound bow is a faster arrow flight accompanied by a flatter trajectory. This has an advantage especially in hunting where the exact placement of the arrow as well as high arrow speeds are desirable.
Generally, the tensioning cable arrangement and the bowstring lie in a plane common to the axis of the arrow. As is known in the art, an offset rod or similar means is generally provided in order to offset the tensioning cable away from the bowstring in order to accomodate a freer release of the arrow.
A disadvantage in offsetting the tensioning cable lies in frictional losses encountered as the cables pass across the offset rod during use. This friction increases the force required to draw the bow and reduces the distance and accuracy of the arrow in flight. Further, the frictional forces greatly increase wear of the cable. These frictional losses and wear forces are compounded by the fact that the tensioning cable moves not only axially (back and forth) but orthogonally (up and down) as well. This, of course, is due to the movement of the limbs towards one another during drawing and away from one another during release of the bow.
Attempts to reduce this frictional contact in the past have generally centered around providing a slide for the offset rod. The slide includes grooves for positioning the tensioning cable to keep the two cable runs from rubbing against one another as they cross the offset rod. As can be appreciated, these guides are of limited effectiveness because they do not significantly address the problem of frictional losses.
A need exists therefore for an improved low friction cable guide. Such a guide ideally would minimize all frictional losses in the tensioning cable and yet be simple, self-contained and easily fitted onto all available compound bows, using offset rods.